1. Field of the Invention
The present invention relates to containers, toner containers containing a toner, and, image forming apparatuses and image forming processes that utilize the toner container.
2. Description of the Related Art
Toner containers containing a toner (hereinafter referring to as “toner containers”), utilized for electrophotographic image forming apparatuses such as copiers, printers and facsimiles, are typically equipped with an inner cap fitted to inner side of an aperture that is provided in the main body of the toner container and also equipped with an outer cap fitted to outer side of the aperture that fits to the inner cap (see Japanese Patent Application Laid-Open (JP-A) Nos. 10-111596 and 2003-84553, for example). In the toner containers, the size of outer diameter of the inner cap and the size of inner diameter of the aperture are produced in almost the same size, thus fitting and fixing of the inner cap to the inner side of the aperture is performed by making use of the resilience of the inner cap.
When the toner containers are attached to inside of an image forming apparatuses, the outer cap is removed from the toner container, and the toner container fitted with the inner cap is installed to predetermined position in the image forming apparatus. Then, the fitting of the inner cap is spontaneously released by action of an attaching-detaching mechanism, and the toner container without the fitting of the inner cap is driven to rotate around the center axis of the toner container, thereby the toner contained in the toner container is discharged from the aperture and the toner is supplied to the image forming portion in the image forming apparatus. The inner cap, of which the fitting is released by action of the attaching-detaching mechanism, remains the condition being supported by the attaching-detaching mechanism, and is fitted again to the inside of the aperture when the toner container is removed from the image forming apparatus after the toner in the toner container is consumed or depleted. Consequently, the leakage of a minor mount of the toner that remains within the toner container may be prevented when detaching the toner containers from the image forming apparatuses.
Such inner caps of the toner containers are usually formed of plastic material, and are typically fitted to toner containers with a fitting force of 1 to 3 kgf. When inner caps of plastic material are subjected a fitting force for long period, the inner caps typically undergo creep deformation, then the fitting force decreases against the aperture, and the inner caps turn into a loose condition. When the toner containers are installed to image forming apparatuses and the toner containers are inclined without outer caps in the loose condition, the inner caps often detach from the aperture, and the toner leaks from the toner containers in some cases.
When the inner caps are loose against the apertures, spaces may be induced between the inner caps and the apertures by a shock caused by dropping the toner container for example, the toner possibly leaks from the space, and the leaked toner tends to reside between the aperture and the outer cap. The condition that toner resides between the aperture and the outer cap may possibly cause smears through dispersing the toner when removing the outer cap. Moreover, the toner between the apertures and the outer caps tend to turn into granulates through flocculating, thus causing a problem of inferior image quality since images are formed from such toner granulates.